diff --git a/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c b/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c
index d72b4852fd0..9631bdfa570 100644
--- a/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c
+++ b/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c
@@ -908,6 +908,9 @@ DRESULT disk_read(BYTE drv, BYTE *buff, DWORD sector, UINT count)
     rt_size_t result;
     rt_device_t device = disk[drv];
 
+    if (device == RT_NULL)
+        return RES_ERROR;
+
     result = rt_device_read(device, sector, buff, count);
     if (result == count)
     {
@@ -923,6 +926,9 @@ DRESULT disk_write(BYTE drv, const BYTE *buff, DWORD sector, UINT count)
     rt_size_t result;
     rt_device_t device = disk[drv];
 
+    if (device == RT_NULL)
+        return RES_ERROR;
+
     result = rt_device_write(device, sector, buff, count);
     if (result == count)
     {
diff --git a/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c b/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c
index 4d4de5e1230..a477851e7e7 100644
--- a/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c
+++ b/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c
@@ -1146,6 +1146,9 @@ DRESULT disk_read(BYTE drv, BYTE *buff, DWORD sector, UINT count)
     rt_size_t result;
     rt_device_t device = disk[drv];
 
+    if (device == RT_NULL)
+        return RES_ERROR;
+
     result = rt_device_read(device, sector, buff, count);
     if (result == count)
     {
@@ -1161,6 +1164,9 @@ DRESULT disk_write(BYTE drv, const BYTE *buff, DWORD sector, UINT count)
     rt_size_t result;
     rt_device_t device = disk[drv];
 
+    if (device == RT_NULL)
+        return RES_ERROR;
+
     result = rt_device_write(device, sector, buff, count);
     if (result == count)
     {